> On Dec 7, 2015, at 7:44 AM, Pratyush Anand <panand@xxxxxxxxxx> wrote: >> On 07/12/2015:06:54:13 AM, peter@xxxxxxxxxxxxxxxxxx wrote: >>> On Dec 7, 2015, at 3:50 AM, Pratyush Anand <panand@xxxxxxxxxx> wrote: >>> >>> Hi tty experts, >>> >>> One of of our application (related to kdump) is failing because of a kernel >>> change in tty layer. It fails to start "Kdump Vmcore Save Service" because it is >>> not able to redirect all standard input/output messages to console (exec &> >>> /dev/console). >> >> What device is /dev/console? > > Its amba-pl011. > >> What device is stdin/stdout? > > stdin is not being used in this case. stdout is again serial console > (amba-pl011). However, if I replace "exec &> /dev/console" with "echo test > > /dev/console", then also it gets same error. Hmm. What's odd is that the race you're observing is only possible when the tty is in final close which isn't true if stdin and stdout and /dev/console all have the same underlying tty device. >> When do you observe this failure? > > During a early systemd service called after init. > > I observe this during kdump operation on seattle platform. When primary kernel > crashes, kdump loads a secondary kernel and initramfs which copies vmcore(memory > dump of failed kernel) to the disk for further analysis. It initializes some > systemd services before starting vmcore copy. One of the early systemd service, > sets up (mainly) STDOUT to /dev/console, so that copy operation message can be > viewed. And this operation fails. I'm traveling right now but will have a chance to spend time on this Wed. I'm sure patches I already posted on list will address this, but I'd like to make sure the cause is a race on final close, and not some other oversight. Regards, Peter Hurley-- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
